24
Examination of witnesses
David Johnson, Pär Larshans and Mike Rose.
Q49 The Chair: Good morning and welcome to the Lords Environment and Climate Change Committee. Today is the fifth session of our inquiry into the efficient use and management of nitrogen in the environment. Today’s session will focus on wastewater. We will take evidence from an expert panel of witnesses. Thank you all very much for taking the time to be with us today. Before we start, I remind everyone that this session is webcast live on Parliament TV and that a transcript will be taken and made public. Our witnesses will be able to review the transcript and make minor amendments if they wish. I also remind all members and witnesses that any relevant interests should be declared the first time they speak.
I am pleased to be able to welcome you to the committee and thank you again for taking time out of your very busy schedules to be with us today. Could each of our witnesses introduce themselves briefly, starting with Pär Larshans?
Pär Larshans: Thank you so much, Chair. I work as head of sustainability for a privately owned company that develops solutions for nutrient recovery. We originated as a waste management company but I understand that in the future circular economy there will be no waste and we will not exist, and we would like to continue as a company for generations to come.
Besides working at this company, I am also global co-chair for the International Chamber of Commerce’s work on the circular economy. We have 45 million companies as members across the world. I am also a member of the steering committee of UNEP’s Global Partnership on Nutrient Management and work closely with UNEP’s global wastewater initiative. Here we can talk about how today’s wastewater treatment plants can become the resource recovery plants of tomorrow. In Europe, I am also a member of the board of Water Europe. Policy dimensions are my key competences, beside circularity.
Mike Rose: I am CEO of UKWIR—the UK Water Industry Research organisation. We are pleased to be here today to provide evidence to the inquiry. I have been in post with UKWIR for four weeks. That also sees me as a board member of the Global Water Research Coalition with organisations from Australia, North America and Europe. UKWIR conducts research for UK and Irish water companies around technical limits, water quality standards, asset performance, sustainability and circularity. We have a diverse programme of research ongoing across a number of relevant topics pertaining to this inquiry. I hope to share some examples with the committee today. Prior to this role, I advised clients globally on sustainability and asset management in water energy, road and rail, and my early career was spent with United Utilities.
The Chair: For the avoidance of doubt, UKWIR is UK Water Industry Research.
Mike Rose: That is correct.
David Johnson: I am technical director at the Rivers Trust, the umbrella organisation for rivers trusts in England and the island of Ireland. I started my career designing and building sewage treatment works, but now more of my focus is working at catchment scale with farmers to deliver a healthier river environment.
The Chair: Excellent—thank you all very much. How do wastewater treatment plants currently process and treat water before it is discharged? How much nitrogen is removed during these processes?
Mike Rose: Wastewater treatment plants can employ a range of processes to undertake treatment. Typically, they involve three stages of treatment. The primary stage focuses on removing large detritus, predominantly inorganic components. The secondary and tertiary treatments remove organic and biological compounds. Specifically on nitrogen removal, the levels that can be achieved vary depending on the technology utilised. That technology and the assets on the site can vary for a whole range of reasons: geography, size, space and when the treatment processes were constructed. Typically, what are referred to as activated sludge plants remove somewhere in the order of 40% to 50% of the nitrogen. Oxygen ditches remove more because there is more anaerobic and anoxic processing. Biological filters, which are typically large rock bed media, remove very little nitrogen.
A number of works within the United Kingdom have received designations over time under the urban wastewater treatment directive to remove nitrates. Typically, these are coastal locations, and specific additional technologies have been installed there to meet those limits. The focus within the UK water sector for the removal of compounds is predominantly around ammonia, and those treatment technologies have been in place for, typically, 10 to 20 years.
The Chair: Do these processes differ much plant by plant? You talked a little about the way that plants in different locations treat the water. I am also interested in the age of plants and the factors that affect the processes they use.
Mike Rose: There are small variants and subtle differences in the way the technology is deployed. For instance, how the air is put into the system can vary. In my experience, the UK asset base is fairly old, particularly with regard to secondary treatment processes. Predominantly, they were installed from 100 to 50 years ago. A lot of that is still maintained and utilised following mechanical and electrical refurbishments to provide the required levels of treatment. The tertiary treatment processes I referred to have typically been added at the back end of processes over time to meet additional standards placed on water companies as a result of the urban wastewater treatment directive, water framework directive et cetera. They range from 20 to 10 years old. Obviously, the improvement programmes that water companies deliver continue to add capability in that space. Performance will depend on what the local operations seek to achieve, how they are operated and the levels achieved, based on the environmental need of the receiving watercourse.
Pär Larshans: It is very important to understand that, for current wastewater treatment plants, the obligation is to do bad things less badly. They also fill in the requirements that are set on how much nitrogen you can release into wastewater. There is no focus on the resource potential, the energy production potential and so forth. Of course, the more you do not do today, the higher the cost will be if you do not change that perspective. I think in responding to later questions we will discuss what is potentially around the corner when we shift the perspective from waste to resources.
The Chair: Mr Johnson, do you have anything to add?
David Johnson: I do not have anything to add on this question.
Lord Krebs: My follow-up question relates to the comment about the age of treatment plants, which I understand is decades for the settlement and probably at least a decade for tertiary treatment. How much technology development is there? It seems rather old-fashioned. I would have thought a lot of research would be going on to be able to do this better. Can you give us an insight into that?
The Chair: Could you answer very briefly, because we will have a question on technologies later?
David Johnson: Certainly there have been enhancements in the way the oxygen in particular is provided to the bacteria, the biology that is undertaken and additional research around chemicals et cetera, but you are correct that the underpinning biology and chemistry are old. Over time, we have sought to optimise the way that biology is undertaken so that plants can be designed in more configurable and scalable ways.
Lord Duncan of Springbank: A lot of the underpinning legislation here is EU-wide. How do different EU nations compare in this area in terms of their technology and the antiquity of some of their processes? Are there champions that are very good or are there people who are very bad?
Pär Larshans: We will come back to this question in part when we talk about the urban wastewater framework directive, but it differs within the EU. I would say that the western parts of the EU are better than the eastern parts. Now, with the new urban wastewater treatment directive, which we will come back to, there will be big changes and a huge demand for nitrogen recovery or removal. There are some good examples; we should look to countries such as Denmark and the Netherlands. In particular on the policy dimension, I recommend Denmark.
Lord Duncan of Springbank: That is helpful.
Lord Rooker: Broadly speaking, what is the difference in nutrient loads between treated and untreated discharges? Is this affected by the age of the equipment?
Mike Rose: I would not say it is affected by the age of the equipment; it is affected by the nature of the catchments, agriculture, industry and population density. The equipment can be optimised to achieve certain performance levels, as I described previously. As Pär says, at the moment the philosophy is about doing the least damage with what is presented to the wastewater treatment works within the mandated standards.
David Johnson: A key point is that, with the infrastructure that collects drainage water, you get systems that combine relatively clean water from drainage with sewage effluent. In those catchments, you get a lot weaker sewage but also a very peaky flow, which can be discharged in combined sewer overflows. The separate systems tend to come from more modern housing. I think that came in during the 1970s. There is a real need to make our catchments less flashy so that less of it goes down the drainage system. As I understand it, that is the difference between the two systems.
Lord Rooker: Can you measure the nutrient loads between the two issues? Is there a broad way of explaining that to a non-expert? From my point of view, it seems obvious that there will be a difference. Is it a measurable difference—a significant one?
David Johnson: We use various standard equations when designing sewage treatment works. They talk about a population equivalent; that is the source of the sewage. Then you add on various different factors to account for the level of infiltration into the system. All of that can be taken into account as you design the treatment works, for both the load and the level of flow coming in.
Pär Larshans: Municipalities are more or less the same, depending on the population, but industrial water can contain high levels of nitrogen. I think that will be the big difference.
The Chair: What are the circumstances under which water is released into water bodies without being treated? We hear so much about discharges into water bodies of substances that should not be there.
David Johnson: You may have seen what we call the sewage map which shows these discharges. We know when the discharge starts and stops. That is to try to inform the public about what is happening. When I used to design sewage treatment works, there was a perfectly good reason why you would design a safety valve in it. You have too much water coming in but it is very diluted, so the idea is that you discharge it during high-flow events and it will have minimal impact.
On the issues we have seen highlighted over the past few years, that is supposed to happen only 10 to 20 times a year. When we started to measure it, we found that it was happening a lot more than that. From going around sewage treatment works as part of my role, my impression is that this is to do with climate change and a changing of that input signal coming into the drainage part of our system, as well as the maintenance and expansion of sewage treatment works to cope with an expanding population. There are probably two things going on there that lead to these discharges.
Mike Rose: To build on that point, much like this inquiry is trying to look at the nitrogen cycle holistically, the management of rainfall in terms of planning policy, the role of wastewater treatment and so on also needs to be considered holistically, so that the right environmental outcomes can be achieved at the right environmental and economic cost.
The Chair: Are septic tanks still a significant source in rural areas? Does that create special problems?
David Johnson: From looking at our modelling results, in general, we see that septic tanks are a very small component of the load. However, they are very important in terms of where they discharge and whether they are being well used or maintained. Typically, they can be maintained very poorly. You get significant areas of the country where there is no mains drainage. In those areas, you can see an impact, for example in the Lake District. They can be significant, but it tends to be localised.
The Chair: Do wastewater companies monitor the water environment into which they make their discharges or do they wait until that information is relayed back to them?
Mike Rose: To the best of my knowledge, water companies monitor their end-of-pipe discharges rather than the environment into which it is received. My understanding is that the Environment Agency monitors river quality, but water companies conduct thousands of tests on a daily basis of both their incoming and outgoing effluent to understand how they perform against their environmental permits.
David Johnson: It is worth saying that over the past three years we have been working on a citizen science project funded by Ofwat. That is an innovation project to try to establish a network of citizen scientists, building on the public engagement there has been on this whole issue. We want to build a citizen science network that delivers data of a known quality that can be used by both the regulator and the water industry to try to identify problems.
Q50 Lord Jay of Ewelme: You talked a lot about emissions. How are emissions from treatment plant processes monitored and reported? You said a little about that already but by whom are they—or should they be—monitored and reported? Do you think the monitoring and reporting are effective?
David Johnson: I understand that there is operator self-monitoring of discharges from sewage treatment works. That is the water industry, is it not? If I am absolutely honest, we have seen some issues with that, because you are then in control of when you monitor and it is possible to change the way the treatment works operate to ensure you get better quality output. That is bad practice and not encouraged, but it is one possible reason why we have seen CSO discharges, which allow water out so you have less water to treat. That is one possibility and we have certainly seen examples of it. I would say that is bad practice. That is the water company element.
Lord Jay of Ewelme: Are there widespread examples or just one or two? Is that a general problem throughout the sector? You can be frank with us.
David Johnson: I think there is too much temptation to do that if you leave this in the control of the water companies. If I were the works manager and had a key performance indicator for discharge consent, I can imagine that I would be tempted to divert part of the flow through the CSOs. That may be what is going on, but we do not know that. We know of specific examples where it has happened, so it feels to me like a potential issue. The fact that we now know what is going out of the CSOs is really the canary in the mine telling us that something is going on, but it has not been designed to work in that way.
The Environment Agency monitors the river. What you want is to measure the river downstream of the mixing zone, so that you can see the actual impact on the river. A while ago I worked at the Environment Agency. The level of monitoring that it does has been falling off for a number of years because it is expensive, so you get much less regular monitoring and so a less rich picture of what the issues are.
Finally, you have this wider network of citizen science and civil society becoming more and more engaged with the issue, going out there and trying to measure, but it is not easy to measure, even professionally, to get good-quality data. Part of why we are working with citizen scientists is to help them measure the right thing and interpret the data correctly. There are all those levels. One other thing about citizen scientists is that they are motivated by monitoring invertebrates in the river, which are the recipients of all the pollution and a good indicator of the combined pressures from both sewage treatment works and agriculture. It is not just sewage treatment; it is agriculture, industry and all these other sources as well.
Lord Jay of Ewelme: You said that Environment Agency monitoring is falling off a bit because it is expensive. If the agency had more staff would it do more? Is it just that it is too expensive and therefore it does other things? This does not seem a priority; what is going through the agency’s mind?
David Johnson: When I was there, it was an efficiency drive to cut costs and save money. As I understand it, there is no income from doing that monitoring so there is no push to do it. It is worth saying that we are just about to start Section 82, which I think will be the biggest global monitoring initiative for water companies, where we will monitor upstream and downstream of each discharge. That initiative is fantastic in terms of the level of data it will give us, because it will give us continuous monitoring, but it also entails an enormous amount of money. We do not believe that some monitoring offers good value for money. It would be great to see that monitoring investment start to look at the whole system and understand how it works, rather than just at sewage treatment works. That would be a great way for it to go.
Pär Larshans: What the European Union is doing is in answer to the demand for nitrous oxide emissions monitoring. Laughing gas emissions monitoring will come. That is part of the new urban wastewater treatment directive. By 2032, it will monitor what the challenges are. Maybe we can come back to this in a later section as well because one big thing we are not really understanding is the huge emissions that go up when we waste nitrogen and do not recover it.
Mike Rose: As I touched on earlier, from a water perspective, water companies monitor ammonia emissions to ensure their compliance with permit standards on a daily basis, both in labs and online monitoring.
Pär touched on nitrous oxide. Within the UK there is no mandatory requirement for monitoring that, but we see a number of our members undertaking monitoring to understand the significance of greenhouse gas emissions from their processes and taking steps to control those emissions. We have helped them to develop a carbon accounting workbook so that they can understand the effect of those emissions on their overall contributions to net zero. For example, during the past five-year investment period, one of our members installed nitrous oxide monitoring at eight of its largest wastewater treatment facilities. That accounts for 40% of its total population served. You will see from that, I hope, that water companies are being proactive in understanding their total impact on the environment rather than just those things mandated by law. They see performance improvement opportunities by understanding this stuff, enabling them ultimately to deliver a better service for their customers and the environment overall.
Lord Jay of Ewelme: Do you think they are doing enough?
Mike Rose: I think it is a step in the right direction. Obviously, a lot of our work with them is to further understand this space—the water sector’s impact on it and the impacts of others. I am sure that, as we will get into in later questions, a big drive here has to be collaboration and collective responsibility for this nitrogen cycle. In a lot of instances, water companies are the end-of-pipe solution to society’s actions and behaviours. There are alternative options out there, which we will get to.
The Chair: Is the monitoring and reporting that is carried out in the public domain? Why do we need citizen scientists to do this work?
David Johnson: Monitoring is in the public domain and it is open data. We can and do draw down on that, using that data to help partnerships around the country understand what the issues are. Monitoring is expensive and is done in just a small number of locations. The beauty of citizen science is that you can get out far wider into the catchment, particularly the upper catchment. A lot of monitoring is focused lower down in the catchment to see the overall impact. Citizen scientists can get out into the upper catchment.
The Chair: Water companies measure the level of nutrients in the effluent discharged into waterways. Would it be helpful if that information were in the public domain? David Johnson, to be clear, is that the data to which you referred, or was that the Environment Agency data?
David Johnson: We tend to use Environment Agency data because we are more interested in the impact on actual water quality in the river than the discharge from treatment works. We make more use of Environment Agency data.
The Earl of Leicester: Our notes under this question say, “It is notable in the context of this inquiry that there are no nitrogen-related targets for treated wastewater under the Environment Act targets”. Is there any hope of that changing shortly?
Mike Rose: I am not able to comment on that.
The Chair: We will put that to Defra and the Environment Agency.
Q51 The Earl of Leicester: I refer to my register of interests as a farmer and landowner. We have a nitrate-vulnerable zone in our land in Norfolk. We are also responsible for two chalk streams. On two of them, we have done some river restoration work with the Norfolk Rivers Trust funded, I think, by Anglian Water.
How effective are upper catchment programmes that work with farmers and landowners in reducing the amount of nitrogen pollution in the water?
David Johnson: I had better take this one. They are effective and you can see how effective they are in small catchments. You can see that in the monitoring and certainly at the field scale. You can see it in groundwater monitoring, although it takes a long time for the signal to come through to groundwater. It is much more difficult to see the signal at the large scale. The reason it is so important to work with farmers is that when you manage the nitrate you can also manage the phosphorus, reduce sediment loss and improve soil health. There are multiple benefits from managing the agricultural input.
One really good example is cover crops, which are grown to ensure that there is no bare soil over winter. These can reduce nitrate leaching into the water by up to 80% at the same time as improving soil health, reducing phosphorus loss, increasing biodiversity and so forth. Another good example of working with farmers is to improve the infrastructure: improving yards and manure management so that the manure is stored safely and can be used at the right time to target crop requirements, efficiently improving resilience.
There are many good reasons for working with farmers. It is effective. We have done some research for Defra over the last couple of years. We worked with over 200 farmers around the country. When we asked the question, “Do you want to work in this way at a landscape scale?”, over 80% of farmers said that they were interested in working in this way; they really wanted to do that, so long as we worked with them in the right way, as they needed, and treated them as a business. That is highly effective but it is difficult to see the signal in big catchments.
Pär Larshans: I totally agree with the focus on measuring for farmers because, as was previously said, that will reduce the cost of fertilising. If you can optimise that, there is a positive incentive. When it comes to investments or doing activities, I would recommend a focus on the wastewater treatment plant and industrial water. That is where you have concentrated loads of nitrogen and you cannot go upstream and change it. There, you are focused on where you have the nitrogen load and you can remove it in different ways. Monitoring for farmers has big potential for increased profits and increased yields in the end.
Mike Rose: We see upper catchment management having the potential to reduce nitrogen pollution. The UK water industry adopted voluntary approaches in working with farmers in catchment-sensitive programmes. More evidence definitely needs to be gathered to better understand the effectiveness of that. We conducted research previously that says catchment management can make a measurable difference in circa 57% of cases, but there are areas of inconclusivity and where no improvement has been observed. From our research, it is a mixed picture, but this can deliver positive results when operated correctly with all participants playing their role.
The Earl of Leicester: Thank you. My second question relates to cost. I will use the example of the tiny chalk stream called the River Stiffkey flowing out into the North Sea. Is it true to say that, naturally enough, water companies direct their investment in improving sewage treatment plants to the much larger conurbations? The Stiffkey has probably seven or eight villages collocated along its banks and each one has a small sewage treatment plant. I have seen the effluent that comes out of those and drips into the river, and it is fairly unattractive-looking stuff.
David Johnson: It becomes increasingly expensive to treat water to a higher standard at smaller treatment works. There are two pressures. If you want to treat water to a higher standard, there is a real temptation to pipe it to the larger treatment works so that you can provide a higher level of treatment. The downside of doing so is that larger treatment works are often at the lower end of the catchment and you are, in effect, removing water from the top end. This is particularly an issue in chalk streams, where you want to see water abstracted and returned as closely as possible so that you have less impact on low flows. There is a real need to implement technologies that are suitable for those rural treatment works.
We are particularly keen on wetland solutions because they are low tech. I must say that there is some disagreement about their level of effectiveness but, because we believe in them as part of the solution, we recently wrote a detailed design guide to help people build wetlands that really work, focused on nutrient removal. Those low-key, low-tech approaches are part of the mix of solutions. We have to take a whole-systems approach; if we just pump the water to the end of the catchment, we create another problem for ourselves, evidently. It is important to look at the whole system. That is why, for me, farming is a critical part of this picture.
Mike Rose: I have seen examples where very high-cost treatment has been required on very small effluent discharges to protect the environment. Water companies are charged with providing best value to customers as they make their decisions on where to deploy investment.
The Earl of Leicester: On Mr Johnson’s very illuminating answers, I have heard—correct me if I am wrong—that sometimes when landowners want to put in these natural systems to treat water there have been objections from either the Environment Agency or, probably more pertinently, the water companies. I hope I am wrong.
David Johnson: No, you have heard correctly. I am afraid there is quite significant pushback from the Environment Agency at the moment. I need to be careful what I say to ensure that I am correct, but there is certainly a lot of resistance. Part of that, it seems to me, is because there is a lack of clarity about how effective these wetlands are. That is one reason we wrote the guide. To be honest, it was turning into a bit of a Wild West, with developers wanting to build houses in nutrient neutrality areas but being blocked. They could not build the houses, so they thought, “We’ll build a wetland and claim lots of nutrient credits”. There was a real temptation to build poorly performing wetlands and claim ridiculous amounts of credit. We wanted to write a detailed design guide to try to move back towards properly designed and maintained wetlands, which we think are a component of the system. The agency is stopping us from publishing our detailed design guide at the moment because there is this confusion. It is very frustrating.
The Earl of Leicester: That is appalling.
Lord Krebs: My question is very brief. If necessary, you may want to answer in writing. Mr Rose, you talked about evidence of what works in upper catchment management. Similarly, Mr Johnson talked about what works in wetland management design. What is the evidence base? Have there been proper studies to evaluate different designs or is it anecdotal, for both wetlands and the upper catchment?
David Johnson: There has been a whole programme of government investment over decades. I used to work for an organisation called ADAS that did agricultural research. We were paid to have experimental farms and really intensive monitoring to see what difference changes in farm practice would make. Those reports were basically used to support the evidence base for the nitrate-vulnerable zones and other regulations. There is a really strong evidence base for what works and what makes a difference. That evidence base is incorporated into industry standard tools that we use—one of them is called Farmscoper—so that we can quantify the reduction in phosphorus, nitrogen and pesticide losses according to different changes in practice.
That is the sort of thing that we like to do when we work with the farming sector. We use these tools to identify for that particular farm business what will give the greatest value for money. We have a good evidence base; it could always be better, but we certainly know what works and what will make the biggest difference.
Mike Rose: As mentioned, we have conducted research on what works with respect to catchment management. I am happy to provide some more detail in writing about that. A number of our members are deploying these technologies and sharing that knowledge across the sector so that others might learn from it. I am happy to pull that together as a written response.
The Chair: We have heard that there is some good work being carried out by South West Water in collaboration with the University of Exeter, working with farmers and landowners upstream. We understand that the results have been very good and cost effective. Could we hear a little bit about that, but not too much because we are, as ever, short on time?
David Johnson: This is “upstream thinking”, working with local rivers trusts and wildlife trusts for more than a decade. It is a real trailblazing initiative. One thing that is so good is that it built capacity for the third sector to work with farmers to reduce inputs at source and have a much more holistic approach. I think it is highly effective and there are many fringe benefits from the investment.
The Chair: What are the next steps from that project, if any?
David Johnson: It is being gradually taken up across the country. There are great examples emerging all around. There is an initiative called the catchment-based approach, which Defra started more than 10 years ago. More than 100 partnerships all around the country have been in place for, as I say, over a decade. The whole idea is to get water companies, farmers, industry and the public to work together to solve a variety of issues. Upstream thinking started that and the catchment-based approach is now growing it, but it is growing it too slowly. We need to improve the strength of that approach.
The Chair: Thank you. That is something that we can put to Defra.
Q52 Lord Krebs: I want to ask you about prioritisation. It appears that managing nitrogen emissions from wastewater has significant cost implications. For example, Ofwat’s spending package review indicates that infrastructure upgrades totalling £35 billion are required to deliver cleaner rivers, with £10 billion for tackling storm overflows and so on. Is there a source of nitrogen emission that should be prioritised from an environmental and cost-effectiveness perspective? In addition, how do nitrate levels in water compare with greenhouse gas emissions to the atmosphere from treatment processes? Who would like to kick off with that?
Pär Larshans: This is my favourite topic. Of course, there is a capex need, but there is also an opex possibility here because today we have only costs. In the next step, when we are recovering and producing nitrogen fertiliser, we will generate income. My company already has an agreement with OMEX, a nitrogen fertiliser company in the UK, that likes to sell everything that we can produce from wastewater treatment plants in the UK.
In the end, the biggest income will come from the fact that we can produce much more energy because we have removed the ammonia and nitrogen in the reactant water, where there are the highest concentrations. You have no limitations on how much energy you can produce. That means that, when you have a wastewater treatment plant with production of biogas, the limiting factor is the amount of ammonia that you then release from the reactant water. Our technology can then remove as much as you want—more than 95%. The more nitrogen load there is, the more nitrogen fertiliser we will then produce. These are the upsides of the new perspective of thinking of reuse, instead of thinking, “Okay, how can I do bad things less badly?” Of course, we need to look at each and every wastewater treatment plant. My biggest problem today is that the procurement process does not allow them to invest in things that produce resources, because that is not their obligation. I would like to come back with more details about that.
Mike Rose: There are a number of trials ongoing to recover ammonia from sewage sludge liquors that can also be used to generate green fuels. That definitely has a positive effect on wastewater treatment performance and, as Pär says, creates an opportunity for revenue upside rather than those liquors being returned to the head of the works. That is being done through the Ofwat innovation fund and Organics Ammonia Recovery programme. We have also conducted research on where the greatest sustainable economic benefit for reuse/recovery can be undertaken across the water cycle, evaluating in excess of 40 technologies to understand what is possible. Nitrogen was part of that study, but there are further mechanisms required to encourage and enable that behaviour to scale.
David Johnson: I certainly agree with treating sludge as a resource but I have a slightly different perspective, perhaps, on prioritisation. We estimate that 70% of the reactive nitrogen in our water systems comes from agriculture, so we absolutely have to work with agriculture. That is difficult and time consuming, and it will take time to show the difference, but there are three or four real benefits that we get out of it. Investing in farm infrastructure is so critical. Tell me if I need to be quicker.
The Chair: We are always up against the clock, but I would like to hear about that. I have few quick follow-up questions.
David Johnson: Invest in farm infrastructure. As you said, treat manures as a resource. Look after them, store them so that they can be used properly and then incorporate them into the soil in a way that reduces greenhouse gas emissions. That avoids some of the trade-offs. Invest in skills in the farming industry. There is so much enthusiasm from the next generation of farmers to be part of the solution; they do not want to be seen as part of the problem. They want to grow food and do that. Also, invest in rural networks. These facilitation groups where you get farmers working together co-operatively at the catchment scale are important. There are many fringe benefits from farmers sharing knowledge and working together.
Lastly, factory farming, that really intensive livestock rearing, is an issue and we cannot escape that. Intensive creation of slurry and so forth is very difficult to use in an efficient agricultural way. We should build on the trend for a lower-meat, lower-dairy diet, which means fewer animals and a more mixed farming system. That is far healthier for our environment as well as for us.
The Chair: I heard what you said, Pär Larshans, about the technologies now available to remove reactive nitrogen from wastewater streams. My concern is more with what David Johnson talked about—the damage done upstream as these reactive compounds of nitrogen pass through ecosystems before they end up in the wastewater treatment works. Those are some of the issues that we have talked about, with the impacts that they have on human health and the planet. Is that correct? I understand that it is useful to have that commercialisation and efficient removal.
Pär Larshans: I will make a short comment on this. I mentioned that the Netherlands and Denmark are maybe the most progressive when it comes to wastewater treatment plants. They are also big farming countries. They see the problem of reducing the national load from the farm side. They needed to take the second-best option or they would have a concentrated load of nitrogen in the wastewater. That is why they are so into this. We should not do only one thing; we need to make sure that we understand this, because the situation is different in different countries. If you have the choice, “Do I need to quit my farming or not?”, you need to make sure that you do whatever you can. Certainly, wastewater is a low-hanging fruit in reducing the national load into the water.
The Chair: Mike Rose, you mentioned some of the new technologies that wastewater companies are looking at. How early stage are those? How close are they to commercialisation?
Mike Rose: I probably need to come back to you with an answer on that one, if I may, Baroness.
The Chair: Excellent—that would be very helpful.
Q53 Baroness Whitaker: I declare that I live in a national park surrounded by run-off. Anaerobic digestion looks like a very useful process. What proportion of treatment plants use it to process sewage sludge and to produce biosolids? If biosolids are not produced and sold to the agricultural sector, what do they do about the sludge?
Mike Rose: The UK water industry operates under a biosolids assurance scheme. Some 73% of the biosolids produced in the UK go through anaerobic digestion and 22% are then processed using lime stabilisation. Of those biosolids produced, 87% of that sludge is recycled to agricultural land as biosolids, 4% is incinerated, 3% goes to industrial use—things like fuel for cement production—and 6% is used in land reclamation.
Why is that? Biosolids have been shown to enhance soil quality and fertility. There is a sludge matrix in place to ensure that the application protects food quality. There is mandatory compliance with the nitrates directive and EU sewage sludge directive in applying that sludge to land. Data is collected on all the sludge in terms of nitrogen, phosphate levels, magnesium and so on. There is best practice guidance developed on how to apply it effectively. Further research is ongoing to understand other substances within biosolids to ensure that a sensible life cycle analysis can be undertaken on future opportunities with respect to biosolids.
Baroness Whitaker: If they do not do all this useful stuff, what do they do with the sludge? Do you know? Is that known?
Mike Rose: As I say, the predominant focus at the moment is recycling to land. There are alternative outlets such as incineration, as previously mentioned, and land reclamation. The sludge is an inevitable by-product of the treatment process. It needs an outlet and to be effectively managed. At the moment—I guess we will get into this—it is considered as a waste and is managed within that framework.
David Johnson: My understanding is that it is fed into landfill if it has heavy metals and so forth. I think that is right. You are frowning at me, so I am not sure about that.
The Chair: Does any of it go for incineration?
Mike Rose: Yes, 4% goes for incineration, for various factors such as land bank availability. Companies look at these things on a case-by-case basis. Yes, some incineration takes place in the UK.
Pär Larshans: On a European level, there is a big difference from country to country. Many countries have a demand for incineration because they do not want to spread it directly on soils. Other countries are the opposite; they really like to spread biosolids. Again, it is about the content of the sewage. There is rising awareness of the challenge of PFAS on our growing and the effect they will have, especially when we spread them on agricultural land, and the consequences of that.
There is ongoing dialogue in the European Union about what the next requirements should be. I am informed that there will probably be some limitation levels set in the circular economy Act being presented in June 2026. The current sewage sludge directive is from 1986 and everybody confirms that this is, to be honest, too old. A lot of research shows that we cannot do the same thing going forward.
Secondly, there is the geopolitical dimension. The phosphorus in the sewage sludge is an extremely valuable resource. We are getting more and more dependent on that. So things are happening at the European level in a very positive way, I believe.
Lord Trees: I have a specific follow-up to that. Should biosolids be tested for a wider range of contaminants? Does a concern about a wider range of contaminants limit the use and increase in uptake?
Mike Rose: At the moment, we are undertaking research with our members on microplastics and other contaminants to better understand the components of biosolids. There is definitely more research needed in that space and further research to explore technologies that might deal with it. That said, the reason those contaminants end up in the sludge is the actions of industry and society, and other inputs into the treatment processes. There needs to be joined-up thinking across the piece to understand where those contaminants are best treated rather than necessarily seeking to solve it at the end of pipe. There is definitely work going on in that space and more understanding is needed.
Pär Larshans: In Sweden, we have a system called REVAQ to make sure that the quality of sewage sludge is good enough to be used as a biosolid. That is working to remove industrial water from wastewater treatment plants where they would like to spread into the system. I encourage you to look into how the REVAQ system operates. It now includes PFAS levels in the requirements, to a certain level. They are a little bit more stringent; there are more demands than the European legislation. It is a qualification system where you can then guarantee that it is safe enough to use.
Lord Trees: Do these considerations affect what you can put into the anaerobic digestion system? That is a wonderful system, it seems to me. To what extent do we integrate waste from animals and humans, and utilise the same capital-intensive plants? Do we mix the two sources particularly? Could we do that as a more cost-effective way of dealing with human waste and animal waste?
Pär Larshans: It is not a problem to combine them, but slaughterhouse residues need to be taken care of in a different way. Otherwise, it is not a problem to take manure in the same way. Of course, there are different conditions. Manure is purer and should not be mixed, I believe, with sewage sludge. There are different systems for that.
Lord Trees: Does it happen at all in existing facilities in the UK?
Mike Rose: I am aware of some work that has mixed biosolids with food waste within UK systems. I am not aware of the agricultural mix. There may be examples.
Pär Larshans: One problem with food waste is that, under current legislation, it is very hard to reuse food waste in anything that will be used for farming. You can use pure produced products, but as soon as it is waste there is a problem. There is a lot going on now when it comes to this change in Europe. In the next step, I think that will be possible because you would like to keep the clean food waste that is not yet wasted and use it for protein production or something else that has a higher value.
Lord Trees: I am thinking of manure and slurry, largely.
Pär Larshans: You should not combine them because manure is often purer than sewage. Manure has a higher value.
The Chair: I just want to bring up the issue of forever chemicals and PFAS. We hear increasingly that one reason the application of biosolids on farms is discouraged is the concentration of these chemicals. Are they a big problem? Just a few words will do.
Pär Larshans: The PFAS headache has just started. In Brussels, PFAS are discussed everywhere. Will they stop the circular transformation? We need to do a lot. Of course, we need to remove PFAS as much as we can from the products that we produce. In the short-term, we need to remove PFAS from the hotspots. That will be the low-hanging fruit to make sure that the water and the sludge used by farmers can be used going forward. Hotspots would be my recommendation as a low-hanging fruit to remove that. My company has focused a lot on nutrient recovery and detoxification; we have a solution to remove between 95% and 97% of both short and long PFAS in hotspots. It is always a problem to cover both dimensions.
Lord Duncan of Springbank: Can I take you back to the earlier point about citizen science? How do you ensure its robustness? How is that robustness accommodated within the points you seek to make? The challenge will always be the distortions or inconsistencies in that sort of approach.
David Johnson: The whole aim of the CaSTCo project is not about making citizen science data perfect; it is about making it of a known quality so that we can use it appropriately. There has been a lot of discussion on this over the last two years. We are just working towards the end of the programme. It is about upskilling citizen scientists. They are not trying to prove that somebody is at fault; they are trying to understand the health of the river and give useful information. It is a work in progress but the enthusiasm there is incredible. A lot of citizen science groups that you work with have professors in them and people of really high calibre. They are more than capable of doing it. We need that network.
Q54 Lord Duncan of Springbank: The EU urban wastewater treatment directive has been revised. What was the revision? What is the upgrade in it and is it applicable? Should the UK follow suit or should we be further ahead?
Pär Larshans: I can start from the European perspective. It came into force at the end of last year, so now we are starting the implementation phase. With nitrogen, we know that the focus is on measuring laughing gas, nitrous oxide emissions, to understand the big impacts. We know from India and Switzerland that laughing gas emissions from wastewater treatment plants are much higher than we thought before. A study from India says that those will even surpass agriculture if we do not do anything, so this is a huge challenge.
What is positive with the urban wastewater treatment directive is the demand for energy neutrality. That means that the wastewater treatment plants need to reduce their energy consumption and produce energy. That is one highlight. Another is the demand for phosphorus recovery. It has not yet said how much phosphorus should be recovered. That is up for discussion, but it is progressing a lot. As I said, there is a lot more of this in western Europe than in eastern Europe. They all need to do a lot, especially the big wastewater treatment plants. They need to reduce their ammonia and nitrogen loads. A lot of things will happen there at the European level.
Mike Rose: From a nitrogen management perspective, any improvements that the UK seeks to make should be based on sound science and environmental need. There can of course be unintended consequences from increasing the treatment burden; it might increase carbon emissions. Solving one problem creates another problem elsewhere within the system. Life cycle analysis is required. We are undertaking research at the moment to explore the technically achievable limits for nitrate removal within wastewater. That provides opportunities in the circular economy, which we have touched on. If the UK does not seek to follow the philosophy of the urban wastewater treatment directive, there is definitely potential for us to fall behind. Maybe there are examples where that directive is perhaps a blunt instrument, for instance, in imposing nitrate removal limits on all wastewater treatment works over 150,000 population-equivalent without necessarily looking at the environmental need and the total emissions load that is required. Some of the research we are doing collaboratively with regulators and other stakeholders will provide an evidence base to better inform the answers for the UK.
Lord Duncan of Springbank: Within an EU context, the challenge will always be that the western EU is comparable in its ability to deliver high-level, high-quality change, and the eastern component of the EU would struggle. The measure across would be an average of where things were. More often than not, the eastern Europeans dropped quite far back as changes to regulations moved forward. They were not moving forward in lockstep at all. That is helpful; thank you.
Q55 Lord Trees: What options and technologies exist for capturing a greater proportion of nitrogen and other nutrients from wastewater? Are there other things that we have not yet talked about that could be explored?
Pär Larshans: When you talk about recovery, you need to use other methods than biological. Biology can only remove. We have developed a method based on chemistry; it uses very little energy and works to a very high degree. As I said before, more than 95% of the nitrogen can be removed with our methodology where we take reactant water. If the wastewater treatment plant decides to use our methodology, it can also, as I said, increase its energy and biogas production a lot, because it does not matter how much nitrogen it puts in in the reactant water phase.
The second dimension is, of course, the phosphorus that we discussed. We are now building two phosphorus plants, one in Germany and one in Sweden, to produce really pure, high-quality end products. It is purer than anything on the market and much purer than from the mining industry. Here we can talk about the geopolitical dimension and being able to resource yourself with phosphorus. It is fully possible. I remember a speech I made for the World Customs Organization in 2022; the headline was “Not only rich people should be able to buy eggs in the future”. We have designed our process to produce feed phosphate quality.
Unfortunately, in the beginning, from the first two plants we will probably sell the phosphorus to Canada because the legislation on a principal level in Europe forbids the use of recycled phosphorus. Here again, the UK can move ahead on this because it is not part of the EU any more. That may be something that we can look forward to. Then suddenly you have a good source of supply for farmers. These are two examples of processes; there are other processes also in place. Many depend on high energy need. Our chemistry is a circular process where we reuse the chemicals in the process. Therefore, the opex are very low with what we have.
Mike Rose: Phosphorus recovery has certainly been explored within the UK. Struvite precipitation, as Pär points out, is a valuable slow-release fertiliser product in that instance. In terms of nitrogen recovery, there are options around source-separated toilets and membrane-based processes for nitrogen recovery. Other nutrients like potassium can be recovered using photobioreactors and microalgae. There are a number of opportunities, with sidestream treatment processes and anaerobic ammonia oxidation ditches to treat some of the sludge liquors and develop high-concentrated ammonia rather than raw sewage. All these things can be looked at as inputs into other parts of the supply chain, but there are barriers to that within the regulation at the moment.
Lord Trees: What are the impediments to this? Are they not technologically advanced enough? Do we need more R&D or is it implementation and investment?
Mike Rose: We need a combination of all of the above, along with end-of-waste regulation in a lot of instances. It can be a very drawn-out process to transform waste into a usable product. There are examples where that has been achieved within the UK but, in the experience of talking to some of our members, it can be a four-year-plus process to navigate that, which comes with a significant amount of effort and energy, adding risk to the process and resulting in the market not being as advanced as it perhaps is in other locations.
Lord Trees: Is pollution swapping a problem here? It has been pointed out by the Sustainable Nitrogen Alliance with regard to some anaerobic digestion that certain innovations can increase greenhouse gas emissions, which to some extent negate the advantages that you get from the nitrogen cycle.
Pär Larshans: Yes, that is correct. Many of these technologies have downsides. One is energy consumption and another is increased laughing gas emissions. Our technology eliminates the risk of laughing gas emissions occurring and can support the plant to reduce the risk that it overshoots in any other part. That was a prerequisite when we developed our process. It is a chemical process, which means it is very robust. We are not dependent on the weather. We know the weather in the UK can be very rainy—I am sorry; I am just kidding. It is important to understand that we need to have a robust system and technology that really works, and that is what we are doing.
Our phosphorus process has no problems with contamination. We separate the chemical processes in different steps. We start with the incineration step and therefore there is no risk for health when it comes to pathogens. The heavy metals are sold back to smelters; the copper will become a new copper cable: we separate all the things in the process.
Lord Krebs: Are any researchers using gene-edited microorganisms to enhance either the recovery of nutrients or their absorption?
Mike Rose: I am not aware of any.
Lord Krebs: Okay, thank you for that no.
Baroness Whitaker: I may have got this wrong, but is there an absence of a level playing field for the water companies? Are good practitioners among water companies penalised in terms of upfront cost if they observe the best practice, or have I misunderstood the inconsistencies that you spoke about?
Mike Rose: Do you mean in terms of nutrient recovery?
Baroness Whitaker: Yes, in terms of how to deal with nitrogen.
Mike Rose: I am trying to think.
Baroness Whitaker: It sounds as if there are not, in terms of spending more on investment.
Mike Rose: I am not sure.
David Johnson: I cannot comment on that.
Q56 Lord Mancroft: Are there any additional resources that could be captured from wastewater to support circular nutrient management such as struvite for phosphate fertilisers?
Pär Larshans: We know that the struvite process recovers part of the phosphorus directly in the wastewater. I have seen studies saying 15% to 20% of it. They say it can be up to 50% but I have not seen that study. If you have used that type of struvite process, the challenge is that the sludge will be of even lower quality. What do we do then with the sludge? Farmers are not that interested afterwards. In some types, with smaller plants, maybe a good way is to use this sludge for landfill.
I briefly talked about our process, which recovers more than 95% of the phosphorus. Another thing that we recover, which I did not mention, is the silica that we separate as part of the process. That can replace cement in concrete production. The Technical University of Denmark has proven that it really works. When you replace cement like that, you have a huge carbon sink in the total process.
Mike Rose: As previously touched on, other nutrients such as potassium are recoverable with microbiological processes, and anammox can be used to recover ammonia. There are other nutrients available for recovery in support of circularity principles.
Q57 Lord Lennie: This has been a fascinating session, so thanks to all of you for your various range as witnesses. In what ways can policy regulation be used to incentivise a more circular approach to nitrogen management reuse and, given Pär’s first comment, make him redundant earlier?
David Johnson: Our favourite is what we call the twin-track approach. On the one hand, that is strong and fair regulation that is enforced and, on the other hand, it is healthy partnership working. We know and we have heard that the low-hanging fruit will come from treating wastewater, but in the long term we have to work with farmers. This twin-track approach has real potential for much bigger benefits to our wider environment, if we invest in it.
On regulation, the farmers we talked to want a level playing field. They want to see the rules enforced where farmers do not play by them. One comment made to us was, “We don’t want to be blamed for the sins of our neighbours”. That is important. There is very low enforcement on farmers at the moment, so there is very little to motivate them to comply with the regulations that are in place. The regulations are very complicated.
Then you need a glass wall between the regulator and partnership working because regulators are not good at building partnerships. They have too much power. As a farmer, you do not want to see a regulator on your land. What else might they see? It is so important to build that partnership working and the ability of farmers to work together so that they can bring in blended finance. The real opportunity that we see is that corporates want to work with farmers. Water companies want to work with them, but they are big beasts with lawyers and all the rest of it. Farmers need to club together. They are scared about being taken for a ride, so it is important that we have this healthy partnership. We see that working already in catchments. It would be great to see it mandated at a policy level so that we saw widespread implementation. That would make a huge difference.
Lord Lennie: What about the revolving door between water companies and regulators?
David Johnson: That is another issue that I saw when I was at the Environment Agency. I do not know how comfortable I am talking about it, but it is definitely an issue. That is why the glass wall between the regulator and partnership really helps. It is so important.
Pär Larshans: It is important to understand that we need to have a market price for the farmer. The farmer will never pay more than market price. With the market price, at the farm level you have an incentive: if the end product has a lower environmental impact or is organic, you can then charge more for what you produce. That is important to understand.
The legislation needs to be based on the Danish model, which now puts a tax on laughing gas emissions. If the wastewater treatment plant then implements technology that eliminates that, it will lower costs. Suddenly, we see now a request for more technologies, especially from Denmark, because we can eliminate those risks. That is one low-hanging fruit to make it happen.
Then we have this energy component to make sure that the wastewater treatment plant becomes a resource plant, producing resources. We must change their perspective so that they can procure that. That is one challenge we see when they are going to use our technology. They are scared to use public procurement because they might be charged with allegations of not just going for the lowest price. Yes, there will be higher capex but there will be much lower opex, and they will generate income. There are, of course, ways to make sure that you can blend and mix different kinds of fertiliser and then have a quota system. The risk with a quota system is that the cost of fertilisers will increase and that will not be accepted by the farmer. Farmers need to get value, otherwise it will not work.
Mike Rose: I hope that you have a sense from what I have said that we, with our members, are doing fascinating research into some of the most innovative methods for nitrogen recovery, and exploring and trialling technologies. Our members are deeply committed to the principles of circularity and supporting effective reuse of resources as much as possible. We did some research with them a little while ago to explore their relative maturity and how their innovations support them to make progress in this area. There is also a sense that this stuff requires support from government to enable it to scale beyond the trial perspective and move forward, unlocking some of the potential that exists.
The Chair: Please write in to the committee with some examples of the good work that has been carried out there. Thank you.
David Johnson: I want to talk a little bit about this, and a concrete example is always good. The Wyre green finance initiative shows the potential for this work. It is the first of its kind and it is bringing in money. It is to deliver natural flood management; that is the focus of this particular one, but it could be for any wider benefits. It brings in money from local authorities, flood and coastal risk management, supermarkets, the insurance industry and government to support farmers to deliver natural flood management. It also brings in money from private investors.
There is a real potential to have blended finance, not just government funding. For the vast majority of farmers we interviewed, their only extra funding was from government. If we want to broaden that out and get it from a much wider source, we have the mechanisms now to bring in that money. We are understanding the problems and opportunities of doing that with these initial studies. There is a real opportunity to scale up these examples.
The Chair: Again, we would be very interested to read more about those examples.
Lord Rooker: Following up an earlier answer that David gave to Lord Lennie, the way you put it was that the farmers are all the little farmers, but the others have their lawyers and are the big boys. My experience as Minister was that it is notoriously difficult to get farmers in the UK to co-operate with each other. Is this not an example that goes beyond the normal aspect of food production? If a group of farmers created a bigger legal entity, there would be an equality between them against the big corporates with their lawyers to deal with this. That has to be good for farmers, has it not?
David Johnson: You are absolutely right. The key will be in the governance of these groups of farmers. When we worked with the farmers, you might not be surprised to hear that some said, “It’s going to be as difficult to work with my neighbours as it is to work with water companies”. It will take time, but this is one of the recommendations that came out of our research. We need to build these governance structures for farmers so that they have a strong voice.
They said to us in the feedback from our final workshops, “This is complicated. We are uncomfortable but we see the opportunity”. The big opportunity for them was to suddenly gain agency or control over the market and be the masters of their own destiny in environmental management. You could see the leading farmers looking at this and saying, “If we can get the support, this could be very significant”.
The Chair: We have a few minutes left. I have a supplementary question and will then give each of you a minute to say what you think are the opportunities to remove barriers and to provide incentives for each of your sectors. Before that, can you explain what is meant by end-of-waste legislation and whether that provides a barrier to what you are trying to achieve?
Pär Larshans: There is a principle here. If you are going to sell this as a product, you need to have an end-of-waste process, and then it needs to be registered and risk-registered. Our processes do that. We have reached end of waste. We are now selling products and can do so. It is a way of going from waste to, in this case, a resource. It is the European definition of what you need to fulfil in order to sell your products. That was a short explanation of what it is.
The Chair: That is excellent. In your view, is a new approach needed?
Pär Larshans: The EU is working hard on that. It has announced three favourite tools coming in over the next four years: an end-of-waste process for everything, green public procurement and producer responsibility. We also see a producer responsibility in the urban wastewater treatment directive when it comes to medicine. These are the three favourite tools of the European Commission.
Q58 The Chair: Before we close the session, could each of you outline maybe two or three things in your sectors where you think there may be opportunities to remove barriers and to improve incentives?
Pär Larshans: The lowest-hanging fruit when it comes to phosphorus is to make sure that we can sell the phosphorus at the quality that we can produce. If we can sell it as a feed phosphate, there will be no cost to society. The potential income will then lead to cities making sure that they put as much phosphorus as possible in the sewage sludge, because the higher the grade of phosphorus in the sludge the higher value it will be. That is a very low-hanging fruit. Of course, we need to have the system in place because we need to incinerate the sludge. There are some investments that need to be done at a certain level. That is a very low-hanging fruit.
Otherwise I would say that we must make sure that we move from wastewater thinking to resource thinking. That needs to be implemented in the public procurement demand or nothing will happen.
Lastly, in my last minute, if the committee is interested, we would be more than happy to give you a tour of our research centre that is part of the Swedish University of Agricultural Sciences in Uppsala, where you can see the research going on in nitrogen, potassium and phosphorus.
The Chair: It is a lovely part of the world, so thank you for that offer.
Mike Rose: I concur that a systems-thinking approach to resource recovery rather than focusing on a fragmented approach would help all participants. Some of the best examples that we have touched on today involved collaboration across the sector. Accelerating that, particularly with respect to development of markets for nitrogen products, would certainly fuel that progress. Those would be my two builds on what has been said. I look forward to following up with the research that I have touched on for the committee to review.
David Johnson: I completely agree with the two previous points. At the same time, we must have that long-term investment in farming because that is how we will get a resilient food supply system. We need to start that now. If nitrogen and phosphorus are the stimulus for us to take a more systems-based approach, that will take us to a much better place for the environment and for our food system.
The Chair: Thank you very much. Before I bring this session to a close, can I encroach on your good will one more time and ask you to write in with some further information on something we touched on earlier—upstream thinking? From a cost perspective, would it be cheaper to improve water quality by influencing farming practices or water treatment? If you could write to the committee with your thoughts on that issue, I would be very grateful.
With that, all that remains is for me to say a heartfelt thank you to our three panellists. It has been a really illuminating session. Thank you very much.
